The Physiological Role of Abscisic Acid in Regulating Root System Architecture of Alfalfa in Its Adaptation to Water Deficit

Alfalfa (Medicago sativa L.) is a perennial leguminous plant, with strong tap root system that plays an important role in alfalfa’s adaptation to drought stress. However, better understanding of functional traits and how these are related whole plant responses order improve pasture productivity under water deficit. Two greenhouse experiments were conducted: Experiment 1 used three alfalfa cultivars four levels soil content treatments investigate herbage productivity, growth point density, residual shoot weight, weight. 2 assessed relationships among root-sourced abscisic acid (ABA), architecture biomass response The results demonstrated was as useful tool tolerant when copied lower content. On average, maintaining 60–65% water-holding capacity had the highest accumulation (6.7 g DM pot-1), growing density (46.5 (1.8 pot-1). At level stress, Medicago L. cv Zhaodong (ZD) Aohan (AH) tended exhibit herringbone branching pattern less tips, forks, altitude, magnitude than Golden empress (GE). Principal component analysis structural equation modeling revealed ABA positively regulated altitude architecture, tips closely associated biomass. It concluded findings can contribute developing optimum irrigation strategies help breeders development new improved tolerance based on hormone, growth.